UA Stratification/Inequality Workshop: 2/17/14

Abstract: In 2009 two British epidemiologists, Richard G. Wilkinson and Kate Pickett, published a book entitled The Spirit Level, which quickly attracted a remarkable amount of attention, both positive and negative, both in the academic and in the public discourse. The book proposes a simple and powerful argument: inequality, more specifically income inequality, is harmful to every aspect of social life. In order to prove their point, the epidemiologists present their evidence in a series of associations between two variables at the time, plotted on a graph, showing comparisons across countries and within the states of the United States. Despite the evident methodological limitations, the authors propose strong causation claims on the detrimental effect of income inequality. Moreover, they rule out a plausible alternative explanation, i.e. the effect of material deprivation (poverty) without having a real measure of poverty. In the meanwhile, over the last decade stratification scholars have demonstrated the nonlinear effect of economic factors, income especially, on health. The results suggest that a relative approach, while fruitful, is best for analyzing dynamics at the top of the income distribution, whereas an absolute approach focused on material deprivation seems appropriate to study the bottom of the distribution. In this paper I correct the limitations of The Spirit Level, trying to catch, where possible, the nonlinearity above mentioned. The results clearly show that poverty is a factor that interacts with and even replaces inequality, whose causal role must be de-emphasized.